U.S. patent number 10,221,915 [Application Number 15/159,983] was granted by the patent office on 2019-03-05 for systems and methods for piston assemblies.
This patent grant is currently assigned to STABILUS, INC.. The grantee listed for this patent is STABILUS, INC.. Invention is credited to Patrick Hartman, Alan Jolley, James T. Kull.
United States Patent |
10,221,915 |
Kull , et al. |
March 5, 2019 |
Systems and methods for piston assemblies
Abstract
Piston assembly includes a piston housing defining an interior
and having a first housing end and a second housing end, a piston
rod having a first rod end extending into the interior and moveable
therein between an extended position toward the first housing end
and a retracted position toward the second housing end, a first
plate joined to the piston rod proximate the first rod end, a
second plate joined to the piston rod and spaced apart a distance
along the piston rod from the first plate, and a piston head
slidably joined to the piston rod between the first plate and the
second plate. A lift assembly including a piston assembly and
configured to provide a damping force to a pivotable body during
pivoting of the pivotable body relative a stationary body between a
closed position and an open position is provided.
Inventors: |
Kull; James T. (Denver, NC),
Hartman; Patrick (Belmont, NC), Jolley; Alan (Gastonia,
NC) |
Applicant: |
Name |
City |
State |
Country |
Type |
STABILUS, INC. |
Gastonia |
NC |
US |
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Assignee: |
STABILUS, INC. (Gastonia,
NC)
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Family
ID: |
53180216 |
Appl.
No.: |
15/159,983 |
Filed: |
May 20, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160265619 A1 |
Sep 15, 2016 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/US2014/066924 |
Nov 21, 2014 |
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61907009 |
Nov 21, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E05F
1/1025 (20130101); F16F 13/007 (20130101); E05C
17/30 (20130101); E05F 3/18 (20130101); F16F
9/5126 (20130101); E05F 3/02 (20130101); E05F
3/10 (20130101); E05F 3/108 (20130101); E05Y
2900/516 (20130101); E05F 3/22 (20130101); E05Y
2900/536 (20130101); E05F 1/1091 (20130101) |
Current International
Class: |
F16F
9/348 (20060101); E05C 17/30 (20060101); E05F
3/02 (20060101); E05F 3/10 (20060101); F16F
9/512 (20060101); E05F 3/18 (20060101); E05F
1/10 (20060101); F16F 13/00 (20060101); E05F
3/22 (20060101) |
Field of
Search: |
;267/64.12,120,221-226,291,293 ;188/67,300 ;16/49,66,82 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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19820404 |
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Feb 1999 |
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DE |
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1419551 |
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Dec 1965 |
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FR |
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Other References
Supplementary European Search Report dated Jun. 21, 2017 in
Application No. EP14864144. cited by applicant .
International Search Report and Written Opinion dated Mar. 3, 2015
in International Application No. PCT/US14/66924. cited by
applicant.
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Primary Examiner: Schwartz; Christopher P
Attorney, Agent or Firm: Baker Botts L.L.P.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of International Patent
Application No. PCT/US2014/066924, filed Nov. 21, 2014, which
claims priority to U.S. Provisional Patent Application No.
61/907,009, filed on Nov. 21, 2013, each of which is incorporated
by reference herein in its entirety.
Claims
The invention claimed is:
1. A piston assembly comprising: a piston housing defining an
interior and having a first housing end and a second housing end; a
piston rod having a first rod end extending into the interior and
moveable therein between an extended position toward the first
housing end and a retracted position toward the second housing end;
a first plate joined to the piston rod proximate the first rod end;
a second plate joined to the piston rod and spaced apart a distance
along the piston rod from the first plate; and a piston head
slidably joined to the piston rod between the first plate and the
second plate; a first energy storage member disposed within the
housing proximate the first housing end between an end wall of the
piston housing and the first plate, and a second energy storage
member disposed proximate the second housing end between an
opposing end wall of the piston housing and the second plate;
wherein at least one of the first and second energy storage members
comprises a spring; and wherein when the piston rod is in the
extended position, the first plate engages the first energy storage
member and when the piston rod is in the retracted position, the
second plate engages the second energy storage member.
2. The piston assembly of claim 1, wherein each of the first and
second plates comprises a washer.
3. The piston assembly of claim 2, wherein at least one of the
first plate and second plate comprises a disc washer.
4. The piston assembly of claim 3, wherein the at least one of the
first plate and second plate further comprises an aperture defined
therethrough.
5. The piston assembly of claim 4, wherein the aperture has a cross
dimension selected to provide a selected amount of damping to the
piston rod when the piston head is in an intermediate position
between the first plate and the second plate.
6. The piston assembly of claim 5, wherein when the piston head is
urged from the intermediate position to the retracted position, a
first amount of damping is provided to the piston rod, the first
amount of damping being greater than the selected amount of
damping.
7. The piston assembly of claim 3, wherein the first plate
comprises a disc washer and the second plate comprises a notched
washer.
8. The piston assembly of claim 3, wherein the second plate
comprises a disc washer and the first plate comprises a notched
washer.
9. The piston assembly of claim 2, wherein each of the first and
second plates comprises a notched washer.
10. The piston assembly of claim 2, wherein each of the first plate
and second plate comprises a disc washer.
11. The piston assembly of claim 1, further comprising a sleeve
surrounding at least a portion of the piston rod and having a first
sleeve end and a second sleeve end, the first plate fixed to the
sleeve proximate the first sleeve end and the second plate fixed to
the sleeve proximate the second sleeve end, the piston head
slidable along the sleeve between the first and second plates.
12. The piston assembly of claim 11, wherein the sleeve has an
outer diameter greater than the first rod end and less than a
remainder of the piston rod.
13. The piston assembly of claim 1, wherein when the piston rod is
urged from the extended position toward the retracted position, the
piston head slides along the piston rod from the first plate toward
the second plate.
14. The piston assembly of claim 1, further comprising a fastener
disposed proximate the first rod end to limit or inhibit movement
of at least the first plate toward the first rod end.
15. The piston assembly of claim 1, wherein the first rod end has a
reduced diameter relative a remainder of the piston rod.
16. The piston assembly of claim 1, wherein when the piston head is
in an intermediate position between the first plate and the second
plate, a first amount of damping is provided to the piston rod, and
when the piston rod moves from the intermediate position toward the
retracted position, a second amount of damping is applied to the
piston rod, the first amount of damping being less than the second
amount of damping.
17. A lift assembly having a first lift end and a second lift end,
the lift assembly configured to provide a damping force to a
pivotable body during pivoting of the pivotable body relative a
stationary body between a closed position and an open position, the
lift assembly comprising: a piston assembly comprising: a piston
housing defining an interior and having a first housing end and a
second housing end; a piston rod having a first rod end extending
into the interior and moveable therein between an extended position
toward the first housing end and a retracted position toward the
second housing end; a first plate joined to the piston rod
proximate the first rod end; a second plate joined to the piston
rod and spaced apart a distance along the piston rod from the first
plate; and a piston head slidably joined to the piston rod between
the first plate and the second plate; a first energy storage member
disposed within the housing proximate the first housing end between
an end wall of the piston housing and the first plate, and a second
energy storage member disposed proximate the second housing end
between an opposing end wall of the piston housing and the second
plate; wherein at least one of the first and second energy storage
members comprises a spring; and wherein when the piston rod is in
the extended position, the first plate engages the first energy
storage member and when the piston rod is in the retracted
position, the second plate engages the second energy storage
member; and a first fitting operably coupled to the piston assembly
proximate the first lift end and configured to engage the pivotable
body; and a second fitting operably coupled to the piston assembly
proximate the second lift end and configured to engage the
stationary body.
18. The lift assembly of claim 17, wherein when the first fitting
is engaged to the pivotable body and the second fitting is engaged
to the stationary body, and when the pivotable body is urged from
the closed position toward the open position to an intermediate
position, the lift assembly provides a first damping force to the
pivotable body.
19. The lift assembly of claim 18, wherein when the pivotable body
is further urged from the intermediate position toward the open
position, the lift assembly provides a second damping force to the
pivotable body greater than the first damping force.
20. The lift assembly of claim 17, wherein when the pivotable body
is urged from the open position to the intermediate position, the
lift assembly provides a third damping force to the pivotable body
greater than the first damping force.
Description
BACKGROUND
The present application relates to systems and methods for piston
assemblies, including such assemblies that can be used in a lift
mechanism for assisting with opening and closing of a large
pivoting body, for example and without limitation a hood for a
class 8 truck.
An exemplary lift mechanism can include a lockable gas spring
arrangement, for example as shown and described in U.S. Patent
Application Publication No. 2013/0187315, which is incorporated by
reference herein in its entirety. In operation, the piston assembly
of the lift mechanism can provide a damped force to a large
pivoting body, for example and without limitation a hood for a
class 8 truck, over a range of motion of the large pivoting body
between an open position and a closed position. When a lift
mechanism is attached to a large pivoting body, such as a hood of a
truck, during operation of the truck, the hood can be subjected to
vibration that can be transferred to the lift mechanism. In this
manner, the piston assembly of the lift mechanism can provide a
damping force in response to the vibration, which can result in
increased wear to the hood and lift mechanism.
As such, there is an opportunity for an improved piston assembly
that can be used in a lift mechanism for assisting with opening and
closing of a large pivoting body, while reducing or preventing wear
on the lift mechanism due to vibrational forces.
SUMMARY
Systems and methods for piston assemblies are disclosed herein.
In accordance with the disclosed subject matter, a piston assembly
is provided. The piston assembly includes a piston housing defining
an interior and having a first housing end and a second housing
end, a piston rod having a first rod end extending into the
interior and moveable therein between an extended position toward
the first housing end and a retracted position toward the second
housing end, a first plate joined to the piston rod proximate the
first rod end, a second plate joined to the piston rod and spaced
apart a distance along the piston rod from the first plate, and a
piston head slidably joined to the piston rod between the first
plate and the second plate.
In some embodiments, the piston assembly can include a first energy
storage member disposed within the housing proximate the first
housing end, and can include a second energy storage member
disposed proximate the second housing end. At least one of the
first and second energy storage members can include a spring. When
the piston rod is in the extended position, the first plate can
engage the first energy storage member, and when the piston rod is
in the retracted position, the second plate can engage the second
energy storage member. When the piston rod is urged from the
extended position toward the retracted position, the piston head
can slide along the piston rod from the first plate toward the
second plate.
In some embodiments, the piston assembly can include a sleeve
surrounding at least a portion of the piston rod and having a first
sleeve end and a second sleeve end. The first plate can be fixed to
the sleeve proximate the first sleeve end. The second plate can be
fixed to the sleeve proximate the second sleeve end. The piston
head can be slidable along the sleeve between the first and second
plates. The sleeve can have an outer diameter greater than the
first rod end and less than a remainder of the piston rod.
In some embodiments, the piston assembly can include a fastener
disposed proximate the first rod end to limit or inhibit movement
of at least the first plate toward the first rod end. The first rod
end can have a reduced diameter relative a remainder of the piston
rod.
In some embodiments, each of the first and second plates can
include a washer. Each of the first and second plates can include a
notched washer. Alternatively, at least one of the first plate and
second plate can include a disc washer. Additionally or
alternatively, the at least one of the first plate and second plate
can include an aperture defined therethrough. The aperture can have
a cross dimension selected to provide a selected amount of damping
to the piston rod when the piston head is in an intermediate
position between the first plate and the second plate. When the
piston head is urged from the intermediate position to the
retracted position, a first amount of damping can be provided to
the piston rod, and the first amount of damping can be greater than
the selected amount of damping. The first place can include a disc
washer and the second plate can include a notched washer.
Alternatively, the second place can include a disc washer and the
first place can include a notched washer. As a further alternative,
the first place and the second plate can each include a disc
washer.
In accordance with other aspects of the disclosed subject matter, a
lift assembly configured to provide a damping force to a pivotable
body during pivoting of the pivotable body relative a stationary
body between a closed position and an open position is provided.
The lift assembly can have a first lift end and a second lift end.
The lift assembly includes a piston assembly. The piston assembly
can include any and all of the features described herein. The lift
assembly includes a first fitting operably coupled to the piston
assembly proximate the first lift end and configured to engage the
pivotable body. The lift assembly includes a second fitting
operably coupled to the piston assembly proximate the second lift
end and configured to engage the stationary body.
In some embodiments, when the first fitting is engaged to the
pivotable body and the second fitting is engaged to the stationary
body, and when the pivotable body is urged from the closed position
toward the open position to an intermediate position, the lift
assembly can provide no damping force to the pivotable body. When
the pivotable body is further urged from the intermediate position
toward the open position, the lift assembly can provide a damping
force to the pivotable body. When the pivotable body is urged from
the open position to the intermediate position, the lift assembly
can provide a damping force to the pivotable body. When the
pivotable body is urged from the intermediate position toward the
closed position, the lift assembly can provide no damping force to
the pivotable body.
Certain variations of the subject matter disclosed herein are set
forth in the accompanying drawings and further description below.
Other features and advantages of the subject matter described
herein will be apparent from the description and drawings, and from
the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an exemplary embodiment of a piston
assembly in accordance with the disclosed subject matter, with
portions of the housing cut away for purpose of illustration.
FIG. 2 is an exploded perspective view of the piston assembly of
FIG. 1, with portions of the housing cut away for purpose of
illustration.
FIG. 3 is a cross-sectional view of the piston assembly of FIG. 1
in an open position.
FIG. 4 is a cross-sectional view of the piston assembly of FIG. 1
in a closed position.
FIG. 5 is a cross-sectional view of the piston assembly of FIG. 1
in a centered position.
FIG. 6 is a perspective view of an alternative embodiment of a
piston assembly in accordance with the disclosed subject matter,
with portions of the housing cut away for purpose of
illustration.
FIG. 7 is a cross-sectional view of the piston assembly of FIG.
6.
FIG. 8 is a side view of a lift mechanism partially in
cross-section, joined to a pivotable body and a stationary body,
and including a piston assembly according to the disclosed subject
matter.
FIG. 9 is a diagram illustrating additional details of exemplary
piston assemblies according to the disclosed subject matter.
DETAILED DESCRIPTION
According to aspects of the disclosed subject matter, systems and
techniques for piston assemblies generally include a piston
housing, a piston rod disposed at least partially within the piston
housing, a first plate joined to the piston rod, a second plate
joined to the piston rod and spaced apart from the first plate, and
a piston head joined to the piston rod and slidable between the
first plate and the second plate.
Piston assemblies according to the disclosed subject matter can be
used in a lift mechanism for assisting with opening and closing of
a large pivoting body joined to a stationary body. For purpose of
illustration only and not limitation, the stationary body can be a
vehicle, such as a class 8 truck, and the large pivoting body can
be a hood for the class 8 truck. An exemplary lift mechanism can
include a lockable gas spring arrangement, for example as shown and
described in U.S. Patent Application Publication No. 2013/0187315,
which is incorporated by reference herein in its entirety.
With reference to FIGS. 1 and 2, an exemplary piston assembly 100
according to the disclosed subject matter is illustrated. The
piston assembly 100 includes a piston housing 102 defining an
interior and having a first housing end and a second housing end.
The piston housing 102 can be configured as a closed housing, and
as such, can be filled with a fluid medium, including but not
limited to, air, compressed gas, oil or any other suitable medium.
Piston housing 102 can be any suitable shape. For example, and as
embodied herein, piston housing 102 can be cylindrical.
Additionally, and as embodied herein, piston assembly 100 includes
a piston rod 108 extending at least partially into the interior of
piston housing 102. As embodied herein, piston rod 108 can has a
first rod end 128 extending into the interior of piston housing
102. Piston rod 108 can have any suitable size and shape. For
example, and as embodied herein, first rod end 128 can have a
diameter less than a diameter of a remainder of piston rod 108. For
purpose of illustration, and not limitation, first rod end 128 can
have a diameter within a range of 4 mm to 16 mm, and as embodied
herein can have a diameter of 8 mm, and the remainder of piston rod
108 can have a diameter within a range of 6 mm to 20 mm, and as
embodied herein can have a diameter of 14 mm. Alternatively, piston
rod 108 can have a constant diameter along its length.
Furthermore, and as embodied herein, piston rod 108 can include one
or more engagements to secure one or more components of piston
assembly 100 to piston rod 108. For example, and as embodied
herein, piston rod 108 can include an engagement region 110
proximate first rod end 128. Engagement region 110 can be any
suitable engagement, and for purpose of illustration and not
limitation, engagement region can be a threated engagement.
In addition, and as embodied herein, piston assembly 100 includes a
first plate 114 joined to the piston rod 108 proximate the first
rod end 128. Piston assembly 100 further includes a second plate
112 joined to the piston rod 108 and spaced apart a distance along
the piston rod 108 from the first plate 114. For purpose of
illustration, and not limitation, first plate 114 can be spaced
apart a distance within a range of 5 mm to 100 mm from second plate
112, and as embodied herein can be spaced apart a distance of 10 mm
from second plate 112. First and second plates 112, 114 can have
any suitable configuration. For example, and as embodied herein,
first plate 114 and second plate 112 each can be configured as
washers. With reference to FIGS. 1 and 2, as embodied herein, first
plate 114 can be configured as a disc washer. Additionally, and as
embodied herein, second plate 112 can be configured as a notched
washer. Alternatively, first plate 114 can be configured as a
notched washer, and second plate 112 can be configured as a disc
washer. As a further alternative, first and second plates 112, 114
each can be configured as a disc washer.
With continued reference to FIGS. 1 and 2, as embodied herein,
piston assembly 100 includes a piston head 116 slidably joined to
piston rod 108 between first plate 114 and second plate 112. In
this manner, the distance between first plate 114 and second plate
112 defines a floating region within which piston head 116 can
slide along piston rod 108, as discussed further herein. The length
of free travel of piston head 116 can be selected and changed to
increase or reduce the amount of undamped movement of the piston
assembly 100 by increasing or decreasing the distance between the
first plate 114 and second plate 112. For purpose of illustration
and not limitation, the length of free travel of piston head 116
between first plate 114 and second plate 112 can be selected within
a range of 5 mm to 100 mm, and as embodied herein, can be 10 mm. As
embodied herein, piston head 116 can include a shoulder 117
protruding outwardly from one or both opposing surfaces thereof.
For purpose of illustration, and not limitation, shoulder 117 can
prevent locking of piston head 116 with first plate 114 or second
plate 112, for example due to hydraulic locking.
Additionally, and as embodied herein, piston assembly 100 can
include a sleeve 118 disposed at least partially about at least a
portion of first rod end 128 of piston rod 108. Sleeve 118 can have
an inner diameter sized to engage piston rod 108 in a frictional
engagement. For purpose of illustration and not limitation, as
embodied herein, sleeve 118 can have an inner diameter of 8 mm and
an outer diameter of 10 mm. First and second plates 112, 114 can be
joined to sleeve 118 by any suitable engagement. For example, first
and second plates 112, 114 can have an inner diameter sized to
engage outer diameter of sleeve 118 in a frictional engagement. For
purpose of illustration and not limitation, as embodied herein,
first and second plates 112, 114 can have an inner diameter of 10
mm. Alternatively, first and second plates 112, 114 can be joined
to sleeve 118 by threaded engagement or any other suitable
engagement. Piston head 116 can have an inner diameter sized to be
disposed about and slide along sleeve 118. For purpose of
illustration and not limitation, piston head 116 can have an inner
diameter within a range of 4 mm to 16 mm, which can be selected to
allow piston head 116 to slide along sleeve 118, if provided,
and/or first rod end 128. Sleeve 118 can be formed of any suitable
material, such as, for purpose of illustration and not limitation
metals, such as steel or aluminum, or polymeric materials, such as
plastic. Alternatively, first and second plates 112, 114 and piston
head 116 can be joined directly to piston rod 108 without sleeve
118 disposed thereon. Additionally or alternatively, piston
assembly 100 can include a fastener 120 secured to engagement
region 110 of first rod end 128. For example, and not limitation,
fastener 120 can be configured as a nut, such as a hexagonal
nut.
Furthermore, and as embodied herein, first and second plates 112,
114 and piston head 116 each can have any suitable size to move
within piston housing 102. For purpose of illustration and as
embodied herein, one or more of first and second plates 112, 114
and piston head 116 can have an outer diameter similar to the inner
diameter of piston housing 102. As such, first and second plates
112, 114 and/or piston head 116 can form a fluid-tight seal with
piston housing 102. For example, and as embodied herein, first and
second plates 112, 114 and piston head 116 each can have an outer
diameter corresponding to inner diameter of piston housing 102. In
this manner, damping forces can be provided by movement of first
and second plates 112, 114 and/or piston head 116, as discussed
further herein. For purpose of illustration and not limitation,
first and second plates 112, 114 and piston head 116 each can have
an outer diameter of 13 mm to 38 mm, which can be chosen to form a
fluid-tight seal between any or all of these components and piston
housing 102. Piston head 116 can further include a gasket 122
disposed therein. Gasket 122 can improve the fluid-tight seal
formed between piston head 116 and piston housing 102. Gasket 122
can be formed from any suitable material to provide a fluid-tight
seal, including but not limited to rubber, urethane,
fluoroelastomer, nylon, polytetrafluoroethylene, or any other
suitable material. First plate 112 and/or second plate 114 can also
include a gasket to improve a fluid-tight seal formed between first
plate 112 and/or second plate 114 and piston housing 102.
In addition, and as embodied herein, first plate 114 and/or second
plate 112 can include an aperture defined therethrough. For
example, and as embodied herein, first plate 114 can include
aperture 126 defined therethrough. The size of aperture 126 can be
selected to adjust an amount of damping provided by the movement of
first plate 114 through the fluid medium in piston housing 102. For
example, increasing the size of aperture 126 can reduce an amount
of damping from movement of first plate 114, via movement of piston
rod 108, as discussed further herein. Conversely, decreasing the
size of aperture 126 can increase an amount of damping from
movement of first plate 114. For purpose of illustration and not
limitation, aperture 126 can have a diameter within a range of 0.1
mm and 3 mm. Additionally, first plate 112 can include a plurality
of apertures 126 to further adjust the amount of damping.
Additionally or alternatively, second plate 112 can include an
aperture therethrough, which can have a diameter selected to
further adjust damping from movement of second plate 112.
Referring still to FIGS. 1 and 2, piston assembly 100 can include
one or more energy storage features to provide energy to first
plate 114, second plate 112, and/or piston head 116. For purpose of
illustration and not limitation, and as embodied herein, piston
assembly 100 can include a first energy storage member 106 disposed
between an end wall of piston housing 102 and first plate 114.
Additionally, and as embodied herein, piston assembly 100 can
include a second energy storage member 104 disposed between an
opposing end wall of piston housing 102 and second plate 112. First
and second energy storage members 104, 106 can be any suitable
energy storage member. For example, and as embodied herein, first
and second energy storage members 104, 106 each can be configured
as a mechanical spring. Alternatively, one or both of first energy
storage member 104 and second energy storage member 106 can be
configured as a compressed gas, electromechanical energy storage,
electromagnetic energy storage or any other suitable energy storage
to provide a force to the first plate 104, second plate 106 or
piston head 116.
Referring now to FIGS. 3-5, exemplary operation of piston assembly
100 is illustrated. With reference to FIG. 3, piston assembly 100
is shown with piston rod 108 in a retracted position. For purpose
of illustration and not limitation, the retracted position of
piston rod 108 can correspond to an open position of a pivotable
body joined to piston assembly 100. In the retracted position,
second plate 112 engages second energy storage member 104, which
can provide tension force, for example to slow the speed of the
pivotable body moving from the closed position toward the open
position and support the pivotable body in the open position.
With reference to FIG. 4, piston assembly 100 is shown with piston
rod 108 in an extended position. When the pivotable body is urged
toward the closed position, piston head 116 engages second plate
112 and damps the motion of piston rod 108. In the extended
position, first plate 114 engages first energy storage member 106,
which can provide a lifting force to urge the pivotable body toward
the open position, for example to assist a user in opening the
pivotable body. First energy storage member 106 can also slow the
speed of the pivotable body moving from the open position to the
closed position.
With reference to FIG. 5, piston assembly 100 is shown with piston
rod 108 in an intermediate position between the extended position
and retracted position. When the pivotable body is in the closed
position, piston rod 108 can oscillate between the extended
position and the intermediate position, which can occur for example
and without limitation, and as embodied herein due to vibrational
forces applied to the piston assembly 100. In the intermediate
position, piston head 116 can float between first plate 114 and
second plate 112. That is, piston head 116 can slide within the
floating region defined between first plate 114 and second plate
112 without engaging either first plate 114 and second plate 112.
In this manner, piston head 116 can be prevented or inhibited from
applying damping force to the piston rod 108 and pivotable body.
When the pivotable body is urged further toward the open position,
for example by lifting the pivotable body by a user, second plate
112 engages piston head 116, which applies a damping force to
piston rod 108, as illustrated for example in FIG. 3. As discussed
herein, first plate 114 and second plate 112 can be selected and
adjusted to allow piston assembly 100 to provide a desired amount
of damping when piston head 116 is in the intermediate position,
for example and without limitation, and as embodied herein due to
vibrational forces, without affecting an amount of damping provided
by piston assembly 100 when piston head 116 is moving to the
retracted position or the extended position, for example and
without limitation, and as embodied herein due to opening or
closing of a pivotable body. That is, as discussed herein, first
plate 114 and/or second plate 112 can be configured as a disc
washer having an aperture 126 sized to select an amount of damping
provided by piston assembly 100 while piston head 116 is in the
intermediate position. For example, and as embodied herein, first
plate 114 can be configured as a disc washer having an aperture
126, and second plate 112 can be configured as a notched washer. In
this manner, piston assembly 100 can provide a selectable amount of
damping in the intermediate position, and as embodied herein, the
selectable amount of damping can be less than the amount of damping
provided by piston assembly 100 when piston head 116 moves to the
retracted position or the extended position by movement of the
piston rod 108.
Alternatively, first and second plates 112, 114 can each be
configured as a disc washer having an aperture 126 sized to select
an amount of damping provided by piston assembly 100 while piston
head 116 is in the intermediate position. In this manner, piston
assembly 100 can be configured to provide a selectable amount of
damping in the intermediate position, and as embodied herein, the
selectable amount of damping in this configuration can be greater
than the amount of damping provided when only one of first and
second plates 112, 114 is configured as a disc washer, yet still
provide less damping than when piston head 116 moves to the
retracted position or the extended position by movement of the
piston rod 108.
As a further alternative, with reference to FIGS. 6 and 7, an
alternative embodiment of a piston assembly 100' can include a
first plate 114' and second plate 112 each configured as a notched
washer. In this configuration, piston assembly 100' can provide
little or no damping while piston head 116 is in the intermediate
position, and can provide desired damping when piston head 116
moves to the retracted position or the extended position by
movement of the piston rod 108. Piston assembly 100' can include
any or all of the features described herein with respect to piston
assembly 100.
FIG. 9 is a diagram illustrating a damping force compared to
velocity of exemplary piston heads moving within the intermediate
position. As shown in FIG. 9, piston assemblies were tested by
oscillating a piston head 116 with a 10 mm within the intermediate
position. A first configuration included a piston assembly having
first and second plates each configured as notched washers. A
second configuration included a piston assembly having a first
plate configured as a disc washer having a 2.5 mm aperture (also
referred to as an orifice) and a second plate configured as a
notched washer. A third configuration included a piston assembly
having a first plate configured as a disc washer having a 1.0 mm
aperture or orifice and a second plate configured as a notched
washer. A fourth configuration included a piston assembly having a
first plate and a second plate each configured as a disc washer
having no aperture or orifice. A fifth configuration included a
piston assembly having a first plate and a second plate each
configured as a disc washer having no aperture or orifice, and
moving within a fluid medium having a greater weight (e.g., an SAE
viscosity grade of 50) than the first through fourth configurations
(e.g., having an SAE viscosity grade of 10).
According to another aspect of the disclosed subject matter, a lift
assembly is provided. With reference to FIG. 8, an exemplary lift
assembly 200 can include a piston assembly according to the
disclosed subject matter. For purpose of illustration and not
limitation, and as embodied herein, lift assembly 200 can include
piston assembly 100, which can include any or all of the features
of piston assembly 100 and/or piston assembly 100' described
herein.
Lift assembly 200 can provide a damping force to a pivotable body
during pivoting of the pivotable body relative a stationary body
between a closed position and an open position is provided. Lift
assembly 200 can include a first fitting 202 joined to piston
assembly 100 proximate a first lift end. As embodied herein, first
fitting 202 can be configured to engage a pivotable body 300. Lift
assembly 200 can include a second fitting 204 joined to piston
assembly 100 proximate a second lift end. As embodied herein,
second fitting 204 can be configured to engage a stationary body
400. First fitting 202 and second fitting 204 can be any suitable
fitting, such as, without limitation, a socket for engagement with
a ball to form a ball and socket joint. Lift assembly 210 can
include a locking element 214. Further details of an exemplary
locking element 214 are described in U.S. Patent Application
Publication No. 2013/0187315, which is incorporated by reference
herein in its entirety.
Referring again to FIGS. 3-5, when first fitting 202 is engaged to
pivotable body 300 and second fitting 204 is engaged to stationary
body 400, and when pivotable body 300 is urged from the closed
position toward the open position to an intermediate position, lift
assembly 200 can provide no damping force to pivotable body 300,
for example via piston assembly 100 and piston rod 108 as
illustrated in FIG. 5. When pivotable body 300 is further urged
from the intermediate position toward the open position, lift
assembly 200 can provide a damping force to pivotable body 300, for
example via piston assembly 100 and piston rod 108 as illustrated
in FIG. 3. When pivotable body 300 is urged from the open position
to the intermediate position, lift assembly 200 can provide a
damping force to pivotable body 300, for example via piston
assembly 100 and piston rod 108 as illustrated in FIG. 4. When
pivotable body 300 is urged from the intermediate position toward
the closed position, lift assembly 200 can provide no damping force
to pivotable body 300, for example via piston assembly 100 and
piston rod 108 as illustrated in FIG. 5.
The piston assemblies and lift assemblies described herein can be
formed from any suitable materials. For example and without
limitation, components of the piston assembly and lift assembly can
be formed from metals, such as steel and aluminum, polymeric
materials, rubber, or any other suitable materials.
As described herein, a piston assembly can be configured to reduce
or eliminate damping forces when a pivoting body, such as a hood,
is in a closed position and subject to vibration, such as during
vehicle operation, while allowing the lift mechanism to provide
damping force when the lid is moved between the open and closed
positions to assist with opening and closing of the hood.
For example and as described herein, the floating piston can thus
allow for little or no damping during vibration, thereby reducing
damaging forces to the hood and attachment components. In this
manner, full damping can be provided during full compression and
full extension travel of the lift mechanism to allow for normal
operation of the truck hood. As such, damping can reduced or
eliminated entirely using the piston assembly and techniques
according to the disclosed subject matter.
The foregoing merely illustrates the principles of the disclosed
subject matter. Various modifications and alterations to the
described embodiments will be apparent to those skilled in the art
in view of the teachings herein. It will thus be appreciated that
those skilled in the art will be able to devise numerous techniques
which, although not explicitly described herein, embody the
principles of the disclosed subject matter and are thus within its
spirit and scope.
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